CVE-2026-64298NFSv4: include MAY_WRITE in open permission mask for O_TRUNC
- 7.1HighCVSS base score
- 0.15%Exploitation in 30 daysEPSS · top 96% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: NFSv4: include MAY_WRITE in open permission mask for O_TRUNC POSIX requires write permission to truncate a file, so an open() that specifies O_TRUNC must be authorized for write access regardless of the O_ACCMODE access mode. nfs_open_permission_mask() builds the access mask passed to nfs_may_open(), which is the local authorization gate for OPENs the client serves itself from a cached write delegation via the can_open_delegated() path in nfs4_try_open_cached(). The mask is derived from O_ACCMODE alone, so an open(O_RDONLY | O_TRUNC) against a file the caller cannot write requests only MAY_READ and passes the local check. The OPEN is then satisfied locally and the truncation is issued to the server as a SETATTR(size=0) over the delegation stateid, which the server accepts under standard write-delegation semantics. POSIX requires that this open fail with EACCES. Include MAY_WRITE in the mask whenever O_TRUNC is set so the local check matches the access the server would have enforced.
Timeline
ID reserved
By Linux
- 6 days later
· 6 days later
Published
- 3 months later
· 3 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.1 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H |
| NVDNVD · Modified | 3.1 | High7.1 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.15% · top 96% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.1.
Affected products
- affected af22f94ae02ab9dd4fd7fe628c8434a59cc293be – < 4817c8974315b666e895b7d1bb83cd3664c323b1
- affected af22f94ae02ab9dd4fd7fe628c8434a59cc293be – < cb148a2762d644bff1894728e8835a9a4b84f9ea
- affected af22f94ae02ab9dd4fd7fe628c8434a59cc293be – < 30fdf4df6c3c00efec947e4ddf97f0fdd4473628
- affected af22f94ae02ab9dd4fd7fe628c8434a59cc293be – < 22c1fd1355ad4ca27aa7f0fa02719122dd92d9de
- affected af22f94ae02ab9dd4fd7fe628c8434a59cc293be – < 6bd7d0a06b53c4e797e1a9cea0d2d41aa1b26230
- affected af22f94ae02ab9dd4fd7fe628c8434a59cc293be – < a937e92c1d00534b5c2e3e9f4381b7e988180797
- affected af22f94ae02ab9dd4fd7fe628c8434a59cc293be – < e36501b7d4abdcd6d69a7cb901b2f286b7a3d041
- affected af22f94ae02ab9dd4fd7fe628c8434a59cc293be – < 5140f099ecd8a2f2808b7f7b720ee1bad8468974
- affected 2.6.24
- unaffected < 2.6.24
- unaffected 5.10.261 – ≤ 5.10.*
- unaffected 5.15.212 – ≤ 5.15.*
- unaffected 6.1.178 – ≤ 6.1.*
- unaffected 6.6.145 – ≤ 6.6.*
- unaffected 6.12.96 – ≤ 6.12.*
- unaffected 6.18.39 – ≤ 6.18.*
- unaffected 7.1.4 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References8
- https://git.kernel.org/stable/c/4817c8974315b666e895b7d1bb83cd3664c323b1 (opens in a new tab)
- https://git.kernel.org/stable/c/cb148a2762d644bff1894728e8835a9a4b84f9ea (opens in a new tab)
- https://git.kernel.org/stable/c/30fdf4df6c3c00efec947e4ddf97f0fdd4473628 (opens in a new tab)
- https://git.kernel.org/stable/c/22c1fd1355ad4ca27aa7f0fa02719122dd92d9de (opens in a new tab)
- https://git.kernel.org/stable/c/6bd7d0a06b53c4e797e1a9cea0d2d41aa1b26230 (opens in a new tab)
- https://git.kernel.org/stable/c/a937e92c1d00534b5c2e3e9f4381b7e988180797 (opens in a new tab)
- https://git.kernel.org/stable/c/e36501b7d4abdcd6d69a7cb901b2f286b7a3d041 (opens in a new tab)
- https://git.kernel.org/stable/c/5140f099ecd8a2f2808b7f7b720ee1bad8468974 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-49010 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://cveledger.app/cve/CVE-2026-64298)Record last updated .